The objectives of this research are to isolate and characterize, and/or to study in other ways, several antigens on the surface of human lymphocytes which are of interest in tumor biology. These antigens include the TH1 and HTL antigens from human T lymphoblastoid cell lines; the EBV-associated antigen(s) present on EHRB-RAMOS and EHRA-RAMOS cells; and the Ia antigen from several different human cell types (B lymphocytes, T lymphocytes, macrophages, myeloid cells and sperm).